Automotive vehicles are commonly equipped with audio radios for receiving broadcast radio frequency (RF) signals and broadcasting audio information to passengers in the vehicle. More recently, satellite based digital audio radio (SDAR) services have become available that offer digital radio service covering a large geographic area, such as North America. Currently, a couple of satellite based digital audio radio services are available in North America, both of which generally employ either geo-stationary orbit satellites or highly elliptical orbit satellites that receive uplinked programming which, in turn, is rebroadcast directly to digital radios in vehicles on the ground that subscribe to the service. Additionally, a number of terrestrial (ground based) transmission repeaters are currently employed in certain areas susceptible to satellite signal blockage to provide a clean and uninterrupted radio signal broadcast. Each vehicle subscribing to the digital service generally includes a digital radio having a receiver and antennas for receiving the satellite and terrestrial signal broadcasts.
The radio receivers are programmed to receive and unscramble the digital data signals, which typically include many channels of digital audio. In addition to broadcasting the encoded digital quality audio signals, the satellite based digital audio radio service may also transmit data within a data bandwidth that may be used for various applications. The additional information may include information about the broadcast, such as song title, artist, and genre of music for display on the radio. The signal may also include further information for other reasons, such as advertising, informing the driver of warranty issues, providing information about the broadcast audio information, and providing news, sports, and entertainment broadcasting, in addition to other information. In addition to providing a general signal transmission to subscribing members, the satellite based digital audio radio service may also make available data bandwidth to certain groups, such as vehicle manufacturers, to provide the ability for the vehicle manufacturer to transmit data to select vehicles. In order to do so, it is generally desirable to be able to target the data communication to specific types of vehicles and/or receivers. Some data may be very sensitive to the vehicle and related systems, thus requiring various levels of security.
There are many secure data communication techniques currently available to encrypt broadcast data, including secure keys, public keys, and public/private key methods. While data encryption techniques are generally employed in various data communication applications, it is desirable to provide for a receiver and method for securely communicating data to selected groups of vehicles and/or receivers in a vehicle.